title: Usefulness of PET/CT for the differentiation and characterization of periampullary lesions.
abstract: OBJECTIVE
  At present, there is no ideal imaging modality for the diagnosis of periampullary lesions. We prospectively evaluated the preoperative diagnostic usefulness of PET/CT for differentiating malignant from benign periampullary lesions.
  
  
  METHODS
  A total of 62 patients aged 27-86 years with periampullary lesions scheduled for surgical resection were consecutively recruited. Dual-phase (18)F-FDG PET/CT was performed in all patients. An additional 3'-deoxy-3'-[(18)F]fluorothymidine (FLT) scan was performed in 21 patients (33.9%). The relationship of visual interpretation, SUV, and lesion to background ratio (LBR) with surgical histopathology diagnosis was evaluated.
  
  
  RESULTS
  There were 36 patients with malignancies, 15 with benign neoplasms, and 11 with benign non-neoplasms. Using visual analysis, FDG PET/CT had good sensitivity (86.1%; 31/36), lower specificity (57.7%; 15/26), and fair accuracy (74.2%; 46/62). Regional lymph node metastases were identified in 7 of 11 patients by FDG PET/CT and only in 1 patient by abdominal CT. On the other hand, hepatic metastasis was detected in 1 patient by FDG PET/CT. Dual-phase FDG (P < 0.001) and FLT (P < 0.05) SUV(max) and LBR were significantly higher in malignant than in benign lesions, and in malignant neoplasms than in benign neoplasms. Although average FLT SUV(max) was significantly lower than the average FDG SUV(max) (P < 0.001), the specificity and accuracy of the former were significantly better.
  
  
  CONCLUSIONS
  FDG PET/CT may help identify patients with periampullary malignancy. FDG SUV(max) and LBR appear to aid in the differential diagnosis and add diagnostic confidence. In addition, higher specificity and diagnostic accuracy may be achieved by additional FLT PET/CT.
authors.affiliation: Department of Nuclear Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Mei-Fang
authors.initials: MF
authors.lastname: Cheng
authors.forename: Hsiu-Po
authors.initials: HP
authors.lastname: Wang
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Tien
authors.forename: Kao-Lang
authors.initials: KL
authors.lastname: Liu
authors.forename: Rouh-Fang
authors.initials: RF
authors.lastname: Yen
authors.forename: Kai-Yuan
authors.initials: KY
authors.lastname: Tzen
authors.forename: Yen-Wen
authors.initials: YW
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014670:Ampulla of Vater / Q000000981:diagnostic imaging* / Q000473:pathology; D003138:Common Bile Duct Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D015224:Dideoxynucleosides; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D015224:Dideoxynucleosides; D019788:Fluorodeoxyglucose F18; C002854:alovudine